#include <stdio.h>
#include <time.h>

int main(void) {
  struct tm t;
  int n;

  t.tm_sec = 0;
  t.tm_min = 0;
  t.tm_hour = 0;
  t.tm_isdst = -1; // 夏令时标识符

  printf("Enter month (1-12): ");
  scanf("%d", &t.tm_mon);
  t.tm_mon--;

  printf("Enter day (1-31): ");
  scanf("%d", &t.tm_mday);

  printf("Enter year (1900+): ");
  scanf("%d", &t.tm_year);
  t.tm_year -= 1900;

  printf("Enter number of days in future: ");
  scanf("%d", &n);

  t.tm_mday += n;
  mktime(&t);
  printf("\nFuture date: %.2d/%.2d/%d\n", t.tm_mon + 1, t.tm_mday,
         t.tm_year + 1900);
  return 0;
}